Thompson led Symantec for ten years, announcing plans in late 2008 to step down the next year as CEO. He joined Microsoft’s board in February of 2012.

He spoke to the Wall Street Journal by telephone from Europe, where he was on a sales trip for Virtual Instruments Inc., the Silicon Valley startup he heads.

Edited excerpts follow:

WSJ: So you’re cutting some nice deals over there for Virtual Instruments?

Thompson: Well, it’s quarter end. I mean, this is the time that is probably the most exhilarating for any company, certainly a startup.

We have had a wonderful, wonderful run for the last five and a half years. I’m hoping that this fiscal year is the one that we prove to the world that we too can look like FireEye (referring to a security startup that recently went public at a lofty valuation).

WSJ: Talk about how you joined the board.

Thompson: Shortly after I announced that I was going to step down as the CEO of Symantec I got a call that says, “gee, would you consider joining the Microsoft board?” And I went, “well, I’m still the chairman here, that just doesn’t seem to work for me as chairman, but give me some time to think about it.”

I have great admiration for the company. I have for a long time.

And as time went on I guess I had originally planned to be chairman for a year. I ended up serving for two years.

And after that second year term was up…I finally decided that this would be an interesting place for me to spend some time.

WSJ: What about the lead independent director position?

Thompson: Well, it’s certainly an occurrence that I did not anticipate.

Two board members decided that they would not stand for reelection for various reasons. And then there was this consensus in the back room that I should be the new lead independent director.

You could quite frankly imagine how flattering that could be. So I obviously accepted readily.

Little did I know that we would have all of the things underway back in September that had transpired in the company over the last few months.

WSJ: What is the give and take on the board like?

Thompson: Well, look, I think what’s important about any board is that you have the diversity of experience which brings richness in the dialogue and discussion around the table.

There’s never an expectation that we will have unanimity on every issue. We certainly want to make sure that we have a collegial, harmonious board, but those things don’t necessarily say everybody has to have the same opinion on every issue. If that were the case, I mean, it would not be a healthy environment and not one that quite frankly I would tolerate.

WSJ: There’s a perception out there that despite all this kind of sort of rhetoric, that Bill Gates is the one who really makes the calls. What’s the reality?

Thompson: Why would I join the board if I was going to be a pawn to somebody else? I don’t need that.

I have enormous respect for Bill. He is a brilliant man who built an unbelievable company. But I didn’t accept the role on the board or the role as the lead independent director to be Bill’s pawn, by any stretch of the imagination.

I think what Bill wants is not people who are going to just cater to him or kowtow to him. What he wants in the boardroom is a good, healthy debate.

If that debate is thoughtful and it brings points of view to the table, he’s certainly willing to listen and participate. And, oh by the way, I’m not willing to be told what the answer is either.

WSJ: What has this summer been like with all the company’s big decisions?

Thompson: I would say it’s been like having almost a second full-time job for me.

I’ve been on the road quite a bit. We have lots of conference calls and discussions. It’s my job to understand where all the directors are on many of the issues before we get to a vote to make sure that I can guide the discussions in a meaningful way.

It’s not, quite frankly, been uncommon for me to spend all day Saturday on the phone or spend a fair amount of time on Sunday mornings talking to someone.

At this point, whatever it takes because this is an awfully, awfully important company, that it’s an icon in American industry, clearly an icon in tech. And so if that means for a few months I have to work a little harder or work a little extra time, it comes with the territory.

WSJ: You’re perceived as having helped rebuild some bridges with Wall Street. Talk about your appearance at the financial analyst meeting.

Thompson: I did not expect, quite frankly, to be surrounded by a bunch of analysts after the session was over. But by the same token I’m not surprised, because only so many people can talk to Steve, and I guess beyond the business unit leaders I was the next logical person that they would gather around.

This is a shareholder-owned company. While Bill and Steve together own quite a bit of it, we cannot ignore the fact that 90% of this company or something close to that is owned by independent shareholders. So it’s important that this board, this management team, all of us listen to what their perspective is.

WSJ: As leader of the CEO search team, do feel like you have the weight of the world on your shoulders?

Thompson: Yes. Look, as I said earlier, this is a very important company, and we’re at a very important moment in time in this company’s history. And so you cannot take lightly the responsibility to help identify and hire the next CEO of Microsoft.

WSJ: Is Microsoft looking to expand the board?

Thompson: Well, we certainly expect that one new board member (from ValueAct) soon, and I think as time goes on what we want to do is have the point of view of our new CEO in the process.

So I think it would be a bit premature for the board to decide, independent of the new CEO, what should the size of the board be, much less what skills and experiences should we bring onto the board.